Preparation of surfactant templated nanoporous silica spherical particles by the Sto¨ber method. Effect of solvent composition on the particle size

Monodispersed nanoporous silica spherical particles with the particle size ranges from 0.01 lm to 1.5 lm were successfully prepared by the Sto¨ber method combined with supramolecular templating approach. The particles formed from homogeneous solutions containing tetraethoxysilane, cetyltrimethylammonium chloride, methanol, and aqueous ammonia solution at room temperature. In the present study, methanol/tetraethoxysilane ratio was the factor to control the particle size. With increasing the methanol/tetraethoxysilane ratios from 1,125 to 6,000, particle size decreased from 1.5 lm to 0.01 lm. The calcination of the particles resulted in the spherical porous silicas with the average pore sizes of around 2.0 nm irrespective of the particle size. The particle morphology retained after the calcination.